import ctypes
import weakref
from collections import namedtuple

from . import lib_openal as al
from . import lib_alc as alc

from pyglet.util import debug_print
from pyglet.media.exceptions import MediaException

_debug = debug_print('debug_media')


class OpenALException(MediaException):
    def __init__(self, message=None, error_code=None, error_string=None):
        self.message = message
        self.error_code = error_code
        self.error_string = error_string

    def __str__(self):
        if self.error_code is None:
            return f'OpenAL Exception: {self.message}'
        else:
            return f'OpenAL Exception [{self.error_code}: {self.error_string}]: {self.message}'


class OpenALObject:
    """Base class for OpenAL objects."""
    @classmethod
    def _check_error(cls, message=None):
        """Check whether there is an OpenAL error and raise exception if present."""
        error_code = al.alGetError()
        if error_code != 0:
            error_string = al.alGetString(error_code)
            # TODO: Fix return type in generated code?
            error_string = ctypes.cast(error_string, ctypes.c_char_p)
            raise OpenALException(message=message,
                                  error_code=error_code,
                                  error_string=str(error_string.value))

    @classmethod
    def _raise_error(cls, message):
        """Raise an exception. Try to check for OpenAL error code too."""
        cls._check_error(message)
        raise OpenALException(message)


class OpenALDevice(OpenALObject):
    """OpenAL audio device."""
    def __init__(self, device_name=None):
        self._al_device = alc.alcOpenDevice(device_name)
        self.check_context_error('Failed to open device.')
        if self._al_device is None:
            raise OpenALException('No OpenAL devices.')

    def __del__(self):
        assert _debug("Delete interface.OpenALDevice")
        self.delete()

    def delete(self):
        if self._al_device is not None:
            if alc.alcCloseDevice(self._al_device) == alc.ALC_FALSE:
                self._raise_context_error('Failed to close device.')
            self._al_device = None

    @property
    def is_ready(self):
        return self._al_device is not None

    def create_context(self):
        al_context = alc.alcCreateContext(self._al_device, None)
        self.check_context_error('Failed to create context')
        return OpenALContext(self, al_context)

    def get_version(self):
        major = alc.ALCint()
        minor = alc.ALCint()
        alc.alcGetIntegerv(self._al_device, alc.ALC_MAJOR_VERSION,
                           ctypes.sizeof(major), major)
        self.check_context_error('Failed to get version.')
        alc.alcGetIntegerv(self._al_device, alc.ALC_MINOR_VERSION,
                           ctypes.sizeof(minor), minor)
        self.check_context_error('Failed to get version.')
        return major.value, minor.value

    def get_extensions(self):
        extensions = alc.alcGetString(self._al_device, alc.ALC_EXTENSIONS)
        self.check_context_error('Failed to get extensions.')
        return ctypes.cast(extensions, ctypes.c_char_p).value.decode('ascii').split()

    def check_context_error(self, message=None):
        """Check whether there is an OpenAL error and raise exception if present."""
        error_code = alc.alcGetError(self._al_device)
        if error_code != 0:
            error_string = alc.alcGetString(self._al_device, error_code)
            # TODO: Fix return type in generated code?
            error_string = ctypes.cast(error_string, ctypes.c_char_p)
            raise OpenALException(message=message,
                                  error_code=error_code,
                                  error_string=str(error_string.value))

    def _raise_context_error(self, message):
        """Raise an exception. Try to check for OpenAL error code too."""
        self.check_context_error(message)
        raise OpenALException(message)


class OpenALContext(OpenALObject):
    def __init__(self, device, al_context):
        self.device = device
        self._al_context = al_context
        self.make_current()

    def __del__(self):
        assert _debug("Delete interface.OpenALContext")
        self.delete()

    def delete(self):
        if self._al_context is not None:
            # TODO: Check if this context is current
            alc.alcMakeContextCurrent(None)
            self.device.check_context_error('Failed to make context no longer current.')
            alc.alcDestroyContext(self._al_context)
            self.device.check_context_error('Failed to destroy context.')
            self._al_context = None

    def make_current(self):
        alc.alcMakeContextCurrent(self._al_context)
        self.device.check_context_error('Failed to make context current.')

    def create_source(self):
        self.make_current()
        return OpenALSource(self)


class OpenALSource(OpenALObject):
    def __init__(self, context):
        self.context = weakref.ref(context)
        self.buffer_pool = OpenALBufferPool(self.context)

        self._al_source = al.ALuint()
        al.alGenSources(1, self._al_source)
        self._check_error('Failed to create source.')

        self._state = None
        self._get_state()

        self._owned_buffers = {}

    def __del__(self):
        assert _debug("Delete interface.OpenALSource")
        self.delete()

    def delete(self):
        if self.context() and self._al_source is not None:
            # Only delete source if the context still exists
            al.alDeleteSources(1, self._al_source)
            self._check_error('Failed to delete source.')
            self.buffer_pool.clear()
            self._al_source = None

    @property
    def is_initial(self):
        self._get_state()
        return self._state == al.AL_INITIAL

    @property
    def is_playing(self):
        self._get_state()
        return self._state == al.AL_PLAYING

    @property
    def is_paused(self):
        self._get_state()
        return self._state == al.AL_PAUSED

    @property
    def is_stopped(self):
        self._get_state()
        return self._state == al.AL_STOPPED

    def _int_source_property(attribute):
        return property(lambda self: self._get_int(attribute),
                        lambda self, value: self._set_int(attribute, value))

    def _float_source_property(attribute):
        return property(lambda self: self._get_float(attribute),
                        lambda self, value: self._set_float(attribute, value))

    def _3floats_source_property(attribute):
        return property(lambda self: self._get_3floats(attribute),
                        lambda self, value: self._set_3floats(attribute, value))

    position = _3floats_source_property(al.AL_POSITION)
    velocity = _3floats_source_property(al.AL_VELOCITY)
    gain = _float_source_property(al.AL_GAIN)
    buffers_queued = _int_source_property(al.AL_BUFFERS_QUEUED)
    buffers_processed = _int_source_property(al.AL_BUFFERS_PROCESSED)
    min_gain = _float_source_property(al.AL_MIN_GAIN)
    max_gain = _float_source_property(al.AL_MAX_GAIN)
    reference_distance = _float_source_property(al.AL_REFERENCE_DISTANCE)
    rolloff_factor = _float_source_property(al.AL_ROLLOFF_FACTOR)
    pitch = _float_source_property(al.AL_PITCH)
    max_distance = _float_source_property(al.AL_MAX_DISTANCE)
    direction = _3floats_source_property(al.AL_DIRECTION)
    cone_inner_angle = _float_source_property(al.AL_CONE_INNER_ANGLE)
    cone_outer_angle = _float_source_property(al.AL_CONE_OUTER_ANGLE)
    cone_outer_gain = _float_source_property(al.AL_CONE_OUTER_GAIN)
    sec_offset = _float_source_property(al.AL_SEC_OFFSET)
    sample_offset = _float_source_property(al.AL_SAMPLE_OFFSET)
    byte_offset = _float_source_property(al.AL_BYTE_OFFSET)

    del _int_source_property
    del _float_source_property
    del _3floats_source_property

    def play(self):
        al.alSourcePlay(self._al_source)
        self._check_error('Failed to play source.')

    def pause(self):
        al.alSourcePause(self._al_source)
        self._check_error('Failed to pause source.')

    def stop(self):
        al.alSourceStop(self._al_source)
        self._check_error('Failed to stop source.')

    def clear(self):
        self._set_int(al.AL_BUFFER, al.AL_NONE)
        while self._owned_buffers:
            buf_name, buf = self._owned_buffers.popitem()
            self.buffer_pool.unqueue_buffer(buf)

    def get_buffer(self):
        return self.buffer_pool.get_buffer()

    def queue_buffer(self, buf):
        assert buf.is_valid
        al.alSourceQueueBuffers(self._al_source, 1, ctypes.byref(buf.al_buffer))
        self._check_error('Failed to queue buffer.')
        self._add_buffer(buf)

    def unqueue_buffers(self):
        processed = self.buffers_processed
        assert _debug("Processed buffer count: {}".format(processed))
        if processed > 0:
            buffers = (al.ALuint * processed)()
            al.alSourceUnqueueBuffers(self._al_source, len(buffers), buffers)
            self._check_error('Failed to unqueue buffers from source.')
            for buf in buffers:
                self.buffer_pool.unqueue_buffer(self._pop_buffer(buf))
        return processed

    def _get_state(self):
        if self._al_source is not None:
            self._state = self._get_int(al.AL_SOURCE_STATE)

    def _get_int(self, key):
        assert self._al_source is not None
        al_int = al.ALint()
        al.alGetSourcei(self._al_source, key, al_int)
        self._check_error('Failed to get value')
        return al_int.value

    def _set_int(self, key, value):
        assert self._al_source is not None
        al.alSourcei(self._al_source, key, int(value))
        self._check_error('Failed to set value.')

    def _get_float(self, key):
        assert self._al_source is not None
        al_float = al.ALfloat()
        al.alGetSourcef(self._al_source, key, al_float)
        self._check_error('Failed to get value')
        return al_float.value

    def _set_float(self, key, value):
        assert self._al_source is not None
        al.alSourcef(self._al_source, key, float(value))
        self._check_error('Failed to set value.')

    def _get_3floats(self, key):
        assert self._al_source is not None
        x = al.ALfloat()
        y = al.ALfloat()
        z = al.ALfloat()
        al.alGetSource3f(self._al_source, key, x, y, z)
        self._check_error('Failed to get value')
        return x.value, y.value, z.value

    def _set_3floats(self, key, values):
        assert self._al_source is not None
        x, y, z = map(float, values)
        al.alSource3f(self._al_source, key, x, y, z)
        self._check_error('Failed to set value.')

    def _add_buffer(self, buf):
        self._owned_buffers[buf.name] = buf

    def _pop_buffer(self, al_buffer):
        buf = self._owned_buffers.pop(al_buffer, None)
        assert buf is not None
        return buf


OpenALOrientation = namedtuple("OpenALOrientation", ['at', 'up'])


class OpenALListener(OpenALObject):
    @property
    def position(self):
        return self._get_3floats(al.AL_POSITION)

    @position.setter
    def position(self, values):
        self._set_3floats(al.AL_POSITION, values)

    @property
    def velocity(self):
        return self._get_3floats(al.AL_VELOCITY)

    @velocity.setter
    def velocity(self, values):
        self._set_3floats(al.AL_VELOCITY, values)

    @property
    def gain(self):
        return self._get_float(al.AL_GAIN)

    @gain.setter
    def gain(self, value):
        self._set_float(al.AL_GAIN, value)

    @property
    def orientation(self):
        values = self._get_float_vector(al.AL_ORIENTATION, 6)
        return OpenALOrientation(values[0:3], values[3:6])

    @orientation.setter
    def orientation(self, values):
        if len(values) == 2:
            actual_values = values[0] + values[1]
        elif len(values) == 6:
            actual_values = values
        else:
            actual_values = []
        if len(actual_values) != 6:
            raise ValueError("Need 2 tuples of 3 or 1 tuple of 6.")
        self._set_float_vector(al.AL_ORIENTATION, actual_values)

    def _get_float(self, key):
        al_float = al.ALfloat()
        al.alGetListenerf(key, al_float)
        self._check_error('Failed to get value')
        return al_float.value

    def _set_float(self, key, value):
        al.alListenerf(key, float(value))
        self._check_error('Failed to set value.')

    def _get_3floats(self, key):
        x = al.ALfloat()
        y = al.ALfloat()
        z = al.ALfloat()
        al.alGetListener3f(key, x, y, z)
        self._check_error('Failed to get value')
        return x.value, y.value, z.value

    def _set_3floats(self, key, values):
        x, y, z = map(float, values)
        al.alListener3f(key, x, y, z)
        self._check_error('Failed to set value.')

    def _get_float_vector(self, key, count):
        al_float_vector = (al.ALfloat * count)()
        al.alGetListenerfv(key, al_float_vector)
        self._check_error('Failed to get value')
        return [x for x in al_float_vector]

    def _set_float_vector(self, key, values):
        al_float_vector = (al.ALfloat * len(values))(*values)
        al.alListenerfv(key, al_float_vector)
        self._check_error('Failed to set value.')


class OpenALBuffer(OpenALObject):
    _format_map = {
        (1,  8): al.AL_FORMAT_MONO8,
        (1, 16): al.AL_FORMAT_MONO16,
        (2,  8): al.AL_FORMAT_STEREO8,
        (2, 16): al.AL_FORMAT_STEREO16,
    }

    def __init__(self, al_buffer, context):
        self._al_buffer = al_buffer
        self.context = context
        assert self.is_valid

    def __del__(self):
        assert _debug("Delete interface.OpenALBuffer")
        self.delete()

    @property
    def is_valid(self):
        self._check_error('Before validate buffer.')
        if self._al_buffer is None:
            return False
        valid = bool(al.alIsBuffer(self._al_buffer))
        if not valid:
            # Clear possible error due to invalid buffer
            al.alGetError()
        return valid

    @property
    def al_buffer(self):
        assert self.is_valid
        return self._al_buffer

    @property
    def name(self):
        assert self.is_valid
        return self._al_buffer.value

    def delete(self):
        if self._al_buffer is not None and self.context() and self.is_valid:
            al.alDeleteBuffers(1, ctypes.byref(self._al_buffer))
            self._check_error('Error deleting buffer.')
            self._al_buffer = None

    def data(self, audio_data, audio_format, length=None):
        assert self.is_valid
        length = length or audio_data.length

        try:
            al_format = self._format_map[(audio_format.channels, audio_format.sample_size)]
        except KeyError:
            raise MediaException(f"OpenAL does not support '{audio_format.sample_size}bit' audio.")

        al.alBufferData(self._al_buffer,
                        al_format,
                        audio_data.data,
                        length,
                        audio_format.sample_rate)
        self._check_error('Failed to add data to buffer.')


class OpenALBufferPool(OpenALObject):
    """At least Mac OS X doesn't free buffers when a source is deleted; it just
    detaches them from the source.  So keep our own recycled queue.
    """
    def __init__(self, context):
        self.context = context
        self._buffers = []  # list of free buffer names

    def __del__(self):
        assert _debug("Delete interface.OpenALBufferPool")
        self.clear()

    def __len__(self):
        return len(self._buffers)

    def clear(self):
        while self._buffers:
            self._buffers.pop().delete()

    def get_buffer(self):
        """Convenience for returning one buffer name"""
        return self.get_buffers(1)[0]

    def get_buffers(self, number):
        """Returns an array containing `number` buffer names.  The returned list must
        not be modified in any way, and may get changed by subsequent calls to
        get_buffers.
        """
        buffers = []
        while number > 0:
            if self._buffers:
                b = self._buffers.pop()
            else:
                b = self._create_buffer()
            if b.is_valid:
                # Protect against implementations that DO free buffers
                # when they delete a source - carry on.
                buffers.append(b)
                number -= 1

        return buffers

    def unqueue_buffer(self, buf):
        """A buffer has finished playing, free it."""
        if buf.is_valid:
            self._buffers.append(buf)

    def _create_buffer(self):
        """Create a new buffer."""
        al_buffer = al.ALuint()
        al.alGenBuffers(1, al_buffer)
        self._check_error('Error allocating buffer.')
        return OpenALBuffer(al_buffer, self.context)
